The purpose of this study is to determine the usefulness of F6-1,25 (OH) 2D3 in controlling psoriasis. Two lesions will be chosen for the study, one will have F6-1,25 (OH) 2D3 in vaseline, the other will receive plain vaseline. At the end of two months, three biopsies will be taken, one biopsy of lesion treated with F6-1,25 (OH) 2D3, one biopsy of lesion treated with vaseline alone and another biopsy of uninvolved normal skin.